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	<title>菜鸟教程(runoob.com)</title> 
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<div class="container">
	<h2>实例</h2>
	<p> .caret 类显示了一个下拉的功能: <span class="caret"></span></p>
	<p> .caret 类在按钮中使用：</p>
	<div class="btn-group">
		<button type="button" class="btn btn-primary dropdown-toggle" data-toggle="dropdown">Menu <span class="caret"></span></button>
		<ul class="dropdown-menu" role="menu">
			<li><a href="#">一个链接</a></li>
			<li><a href="#">另一个链接 link</a></li>
			<li><a href="#">其他功能</a></li>
		</ul>
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